In a move that could cost him his seven Tour de France titles, former cyclist Lance Armstrong is now facing formal doping charges from the U.S. Anti-Doping Agency.

In a 15-page letter dated June 12 to Armstrong and others, the USADA said that it had the cyclist's blood samples from 2009 and 2010 and that they were consistent with "blood manipulation."

Armstrong is accused of using the blood booster EPO, blood transfusions, a human growth hormone, testosterone and steroids. Such doping would have made him a stronger and faster racer. He and his lawyer have vehemently denied that the seven-time Tour winner has ever participated in doping.

The letter also said Armstrong and five others -- including three doctors and a trainer -- had been involved in a team-wide doping program from 1998 to 2011 and that the USADA had "witnesses to the conduct."

In a statement today, Armstrong called the USADA's allegations "baseless" and "motivated by spite."

"I have never doped, and, unlike many of my accusers, I have competed as an endurance athlete for 25 years with no spike in performance, passed more than 500 drug tests and never failed one," Armstrong said.

"This is the product of malice and an unhealthy obsession with Lance. The more tests that he passes the more they seem to believe he is guilty," said Armstrong's lawyer Bob Luskin. "They've made a wicked bargain with other riders, telling them that they will not be charged if they implicate Lance and they will be banned if they don't. Nothing good or honest or fair or truthful can come out of this process. Lance hasn't ever doped and his innocence was supported by more than 600 successful drug tests."

"The charges are new in the sense they have just been filed, but they are the same old charges from the same old people," Luskin said.

Luskin said that while the USADA could not bring criminal charges, it had the authority to regulate sports that agree to be governed by it. The agency has the ability to strip Armstrong of his bike title and the right to ban him from participation in triathlons.

In February, a federal investigation against the cyclist did not result in his indictment. Doping is not a crime, but investigators could have charged him with money laundering and conspiracy to hide any use of performance-enhancing drugs.

Sources told ABC News that while the investigation had proved that Armstrong had doped, the U.S. attorney did not believe there was enough evidence on the other allegations.

The investigation included several teammates -- including Tyler Hamilton and Floyd Landis -- who said that they'd seen Armstrong use a variety of performance-enhancing drugs when they raced.

"He took what we all took," Hamilton told CBS' "60 Minutes" in 2011. "There's really no difference between Lance Armstrong and the rest.... There was EPO, there was testosterone and I did see a blood transfusion."

In a 2010 interview with "Nightline," Landis described in detail how he said he and fellow cyclists -- his former friends -- doped during the Tour de France.

At the time, Landis claimed Armstrong -- his former teammate and friend -- transfused his own blood, a banned practice that gives endurance athletes an advantage by increasing their red blood cell count and, therefore, their endurance. He also claimed Armstrong used a banned substance called EPO, which provides a similar effect as a transfusion. Lance Armstrong and his lawyer both have repeatedly denied that he has ever cheated.